The present invention is drawn to a lymphocyte-derived antimicrobial protein (LDAP) which is useful in the prevention and treatment of bacterial, viral and fungal pathogen caused infection in food and companion animals. The present invention is further drawn to nucleic acids and nucleic acid analogues encoding the protein and methods of isolating the protein and expressing the protein as well as antibodies which recognize the protein.
Bacterial, viral and fungal infections which effect food and companion animals are of clear and obvious concern throughout the world. Bacterial infections of concern include but are not limited to mastitis, including bovine mastitis, respiratory diseases, enteritis and septicemia. Viral diseases include, but are not limited to, leukosis virus, respiratory disease, rabies, rhinotracheitis, FeLV, distemper and warts. Fungal diseases include, but are not limited to, ringworm, histoplasmosis, systemic mycoses and dermatitis.
As one example of a bacterial infectious condition, bovine mastitis is the most important infectious disease affecting both the quality and quantity of milk produced in the world. Bovine mastitis affects every dairy farm and approximately 38% of all cows. Mastitis can cause destruction of milk-synthesizing tissues, resulting in decreased milk production and altered milk composition. Depending on the duration and severity of disease, the productive performance of infected dairy cattle may be diminished permanently. Consequently, mastitis continues to be the greatest deterrent to profitable dairy production. On average, losses associated with mastitis will cost American dairy producers about 2 billion dollars annually; worldwide losses are estimated at 25 billion dollars annually.
In spite of the severe economic impact of this disease on the dairy industry, the only widely accepted methods of mastitis control are based on post-milking teat disinfection and antibiotic therapy. These methods are not always cost effective due to milk loss during such treatments. There is also a growing concern over the presence of drug residues in the food supply out of a concern for public safety. It becomes obvious that an effective, safe, and economical preventative which reduces the dairy industry""s dependence on chemotherapeutics is a major unfilled need of the industry. Chemotherapeutics refers to the treatment of diseases with chemical agents.
The present invention is drawn to a purified soluble lymphocyte-derived antimicrobial protein (LDAP) having the following properties
a molecular weight of 16 kD or 30-50 kD when associated with bovine serum albumin (BSA),
a susceptibility to inactivation by heat treatment at 56xc2x0 C. for 30 minutes or by trypsin,
expression primarily by CD2+, CD3xe2x88x92, cytokine stimulated cells, and
antimicrobial activity against both Gram-positive and Gram-negative bacteria; or
a derivative of said protein which contains one or more conservative amino acid changes and
which has antimicrobial activity against both Gram-negative and Gram-positive bacteria.